Absorption power measuring device

ABSTRACT

In an apparatus for measuring absorbed power including an electromagnetic field probe  1  fixedly mounted within a head simulation phantom  2  which simulates the configuration and the electromagnetic characteristics of a head of a human body, and wherein the strength of an electric field or a magnetic field of a radio wave externally irradiated upon the head simulation phantom  2  is measured by the electromagnetic field probe  1,  and the power of the radio wave absorbed by the head is estimated on the basis of measured values, the head simulation phantom  2  comprises a solid dielectric  10 ′ which simulates the configuration and the electromagnetic characteristics of a head of a human body or a liquid dielectric  10  which simulates the electromagnetic characteristics of a head of a human body and which is filled in an enclosed vessel  10  which simulates the configuration of a head of a human body. The volume of the solid dielectric  10 ′ or the volume of the enclosed vessel  11  is equal to or less than 5×10 5  mm 3 .

TECHNICAL FIELD

[0001] The present invention relates to an apparatus which uses aphantom simulating the electromagnetic characteristics of a human bodyto measure the amount of absorption by the human body of a radio wave orwaves radiated from a radio transmitter which is operated in thevicinity of the body through a relative scan of the phantom and theradio transmitter.

BACKGROUND ART

[0002] In the prior art practice, the power absorbed by a human body,for example, by the head of the human body, has been estimated byconstructing a head simulation phantom which simulates the configurationand the electromagnetic characteristics of the head of the human bodyand measuring the amount of power absorbed by the phantom.

[0003] A conventional example of the prior art will be described withreference to FIG. 1. A head simulation phantom 2 is constructed byforming a recess 12 configured to divide the head of the human body intotwo equal parts laterally in a top surface of a vessel 11 and fillingthe recess 12 with a liquid medium 10 which simulates theelectromagnetic characteristics of the head. By way of example, theliquid medium for a 900 MHz solution comprises 56.5% of sucrose, 40.92%of deionized water, 1.48% of sodium chloride, 1.0% of hydroxyl celluloseand 0.1% of bactericide as disclosed in a literature IEC/PT62209,“Procedure to Determine the Specific Absorption Rate (SAR) for Hand-heldMobile Telephones” or the like. A radio transmitter 3 which represents aradio wave radiation source is secured to the bottom surface of thevessel 11 on the outside thereof at a location central of the vessel 11or which corresponds to the ear of the head of the human body. Anelectromagnetic field probe 1 which detects an electric or a magneticfield is inserted into the liquid medium 10 and is scanned in a planewhich opposes the radio transmitter 3. In this instance, the headsimulation phantom 2 and the radio transmitter 3 are separately securedand only the electromagnetic field probe 1 is moved as indicated byarrows 8 for purpose of scan. A resulting detected value of theelectromagnetic field probe 1 is squared, and the squared value ismultiplied by a calibration facter to determine the absorbed power whichoccurs within the head simulation phantom 2. Broken lines 6, shownlaterally offset, represent the locus of scan of the probe 1, and thiscorresponds to the measurement of absorbed power from the radio wave ina situation that the mobile telephone is located close to the ear of thehead of the human body during the transmission and reception with theantenna (not shown) of the radio transmitter 3 extending in a directionthrough the casing of the radio transmitter 3 which runs substantiallyparallel to the bottom surface of the vessel 11.

[0004] The head simulation phantom 2 shown in FIG. 1 is filled with theliquid medium 10, and is inconvenient in its handling. Since the probe 1is moved within the liquid medium 10 for purpose of scan andmeasurement, the liquid medium 10 remains open to the air, and therearises a problem that the liquid medium 10 may be evaporated to cause anaging effect of the electromagnetic characteristics thereof.

[0005] Another example of the prior art will be described with referenceto FIG. 2. A head simulation phantom 2 which simulates the configurationand the electromagnetic characteristics of the head of the human body isconstructed, and an electromagnetic field probe 1 is inserted into anopening 21 formed in the phantom 2. The electromagnetic field probe 1 islocated close to the ear of the head simulation phantom 2, while a radiotransmitter 3 which represents a radio wave radiation source ispositioned on the external surface of the head simulation phantom 2close to the ear. The transmitter 3 is moved vertically andback-and-forth, as indicated by arrows 8, for purpose of two-dimensionalscan while deriving a detected value from the electromagnetic probe 1,and multiplying a calibration factor to the square of the detected valueto determine the absorbed power. The locus of scan for this case isillustrated by broken line 6, shown laterally offset. It is assumed inFIG. 2 that a mobile telephone is used as the radio transmitter 3 withan antenna extended from the telephone case to simulate the manner ofuse of a mobile telephone.

[0006] The phantom 2 shown in FIG. 2 simulates the head of the humanbody by a spherical solid dielectric 10′ or by a liquid dielectric(liquid medium) 10 which fills the interior of a spherical vessel. Thesolid dielectric 10′ has a dielectric constant εr′=52 and a dielectricloss tanδ=55% (at 900 Mhz), for example, and comprises 57% ofpolyvinylidene fluoride, 10% of ceramic powder and 33% (volume %) ofgraphite powder, as disclosed in a literature by H. Tamura, Y. Ishikawa,T. Kobayashi and T. Nojima “A Dry Phantom Material Composed of Ceramicand Graphite Powder,” IEEE Trans. Electromagn. Compat., Vol. 39, No.2,pp132-137, May 1997 or the like.

[0007] Assuming that the head phantom2 is formed with a size simulatingthe head of the human body, or with a sphere having a diameter of 200mm, it contains a volume of 4×π×{(200/2)mm}³/3. The dielectric whichsimulates the electromagnetic characteristics of the head of the humanbody has a density which is equal to about 0.002 g/mm³ for the soliddielectric 10′ and which is equal to about 0.001 g/m³ for the liquiddielectric (liquid medium). Accordingly, the head simulation phantom 2has a weight which is equal to the volume 4×π×{(200/2)mm³/3 multipliedby the density 0.002 g/mm³ or 8400 g for the solid dielectric 10′. Sincethe liquid dielectric 10 has a density which is nearly one-half that ofthe solid dielectric 10′, the phantom will have a weight which is nearlyone-half that of the solid dielectric 10′ phantom. Thus, a conventionalhead simulation phantom 2 has a weight which is as high as 4200 g or8400 g, and presented an inconvenience in its handling andtransportation.

[0008] The purpose of measuring the absorbed power is to know how muchof a radio wave is absorbed by the human body during the use of a mobiletelephone or a transceiver, and the measurement takes place in aso-called near field in which a distance from a radio wave radiationsource to the phantom 2 is normally very small. As a consequence, thereis a great influence that the reproducibility of positional relationshipbetween the radio transmitter 3, the head simulation phantom 2 and theelectromagnetic field probe 1 has upon the reproducibility of results ofmeasurement. In other words, if there is a relatively small shift in therelationship, there occurs a change in the reflection characteristic ofthe phantom 2, producing a change in the distribution of the radiatedelectromagnetic field. If the radio transmitter 3 is held by the hand 4′of a measuring personnel as indicated in FIG. 3, it is difficult tomaintain a correct position of the transmitter relative to the phantom2, and a good reproducibility of measured values cannot be guaranteed.There also occur influences that the radio wave radiated from the radiotransmitter 3 is absorbed by the hand 4′ of the measuring person andthat the current distribution on the antenna 5 of the radio transmitter3 may be changed due to the hand 4′ of the measuring personnel. Wherethe radio transmitter has a bulky volume or heavy, it may be difficultto conduct a spatial scan of the radio transmitter 3 relative to thephantom 2 by hand 4′.

[0009] Conversely, if the radio transmitter 3 is fixed while theabsorbed power measuring assembly 7 comprising the head simulationphantom 2 and the electromagnetic field probe 1 scans through atwo-dimensional movement relative to the radio transmitter 3, it is atroublesome operation to perform the measurement by manually moving andscanning the absorbed power measuring assembly 7 when the headsimulation phantom 2 has a weight which is as high as 4200 g or 8400 gas described above.

[0010] It is an object of the present invention to provide an apparatusfor measuring absorbed power which permits a scan through a relativemovement between an absorbed power measuring assembly comprising asimulation phantom and an electromagnetic field probe and a radiotransmitter to be performed in a relatively simple manner.

DISCLOSURE OF THE INVENTION

[0011] According to one aspect of the present invention, in an apparatusfor measuring absorbed power in which an electromagnetic field probe isinserted inside a phantom which simulates the configuration and theelectromagnetic characteristics of part of a human body, and the fieldstrength of an electric field or a magnetic field of a radio wave whichis externally irradiated upon the simulation phantom is measured, andthe power of the radio wave which is absorbed by the part of the humanbody is estimated on the basis of measured values, the simulationphantom has a volume which is equal to 5×10⁵ mm³ or less.

[0012] More preferably, at least part of the simulation phantom which isdisposed opposite to the radio transmitter is coated by a spacercomprising a material of a lower dielectric constant than the phantom.

[0013] According to another aspect of the present invention, in anapparatus for measuring absorbed power in which an electromagnetic fieldprobe is inserted inside a phantom which simulates the electromagneticcharacteristics of a human body, the field strength of an electric fieldor a magnetic field of a radio wave which is externally irradiated uponthe phantom is measured by the electromagnetic field probe, and thepower of the radio wave which is absorbed by the human body is estimatedon the basis of measured values, there is provided a scan mechanismwhich performs a relative movement between the phantom and the radiotransmitter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a perspective view of a conventional apparatus formeasuring absorbed power using a head simulation phantom in which aliquid dielectric (liquid medium) is used;

[0015]FIG. 2 is a perspective view of a conventional apparatus formeasuring absorbed power in which an electromagnetic probe is insertedinside a head simulation phantom and an absorbed power measuringassembly is fixed while spatially scanning a radio transmitter.

[0016]FIG. 3 is a perspective view of a conventional apparatus formeasuring absorbed power in which a radio transmitter is manually heldby a measuring personnel for purpose of scan;

[0017]FIG. 4 illustrates a power absorption by a head simulationphantom;

[0018]FIG. 5 shows a layout of a calculation model including a headsimulation phantom and a half-wavelength dipole antenna acting as aradio wave radiating source in order to calculate a distribution of theelectromagnetic field within the phantom;

[0019]FIG. 6 graphically shows a normalized power calculation value atthe location of the electromagnetic field probe which is to be disposedinside the head simulation phantom, plotted against an antenna positionas measured along the length of the antenna;

[0020]FIG. 7A is a cross section showing an example of an absorbed powermeasuring assembly with the apparatus according to the invention whichuses a solid dielectric 10′;

[0021]FIG. 7B is a cross section showing an example of an absorbed powermeasuring assembly in the apparatus of the invention which uses a liquidmedium 10;

[0022]FIG. 8 is a perspective view illustrating the set-up in which aradio transmitter is fixed while an absorbed power measuring assemblyaccording to the invention performs a spatial scan;

[0023]FIG. 9 is a cross section showing an example in which a spacer isapplied to part of a phantom;

[0024]FIG. 10 is a cross section showing an example in which the entiresurface of the phantom is covered by a spacer;

[0025]FIG. 11 illustrates that the portion of the phantom which iscovered by the spacer is maintained in contact with the radiotransmitter while it is subject to a moving scan, permitting a constantdistance to be maintained between the phantom and the radio transmitter;

[0026]FIG. 12 illustrates the use of detachable spacers having differentthicknesses in order to change the distance between the head simulationphantom and the radio transmitter, FIG. 12A being a cross section for asmall spacing, FIG. 12B a cross section for an intermediate spacing andFIG. 12C a cross section for a greater spacing.

[0027]FIG. 13 is a perspective view of part of an exemplary spacerhaving a variable thickness;

[0028]FIG. 14 illustrates the use of the spacer shown in FIG. 13,allowing the distance between the head simulation phantom and the radiotransmitter to be changed;

[0029]FIG. 15A shows another example of a phantom with a handle grippedby a measuring personnel;

[0030]FIG. 15B shows a further example of a phantom with a handle whichis gripped by a measuring personnel;

[0031]FIG. 16A shows a simulation phantom formed by an ellipsoid;

[0032]FIG. 16B shows a simulation phantom formed by a regular cube;

[0033]FIG. 16C shows a simulation phantom formed by a rectangular body;

[0034]FIG. 16D shows a simulation phantom formed by a solid cylinder;

[0035]FIG. 17A is a perspective view of a head simulation phantom whichrelatively closely simulates the configuration of a head and having ameasuring plane which corresponds to the front of a face;

[0036]FIG. 17B is a perspective view of a head simulation phantom whichrelatively closely simulates the configuration of a head and having ameasuring plane which corresponds to the side of a face;

[0037]FIG. 18A is a perspective view of an embodiment of the secondinvention;

[0038]FIG. 18B is a perspective view showing an exemplary engagementretaining mechanism for maintaining a slidable relationship between adrive bar and a retainer with the bottom surface of a retainer 4 shownin FIG. 18A disposed upside;

[0039]FIG. 19 illustrates an example of a range of measurement obtainedwhen the absorbed power measuring assembly 7 undergoes a two-dimensionalscan in the arrangement of FIG. 18A;

[0040]FIG. 20 is a cross section showing an example of an absorbed powermeasuring assembly 7 which uses a liquid medium 10;

[0041]FIG. 21 is a perspective view of an exemplary absorbed powermeasuring assembly in which a plurality of electromagnetic field probesare fixedly mounted as a linear array within the phantom;

[0042]FIG. 22 is a perspective view of another absorbed power measuringassembly in which a plurality of electromagnetic field probes arefixedly mounted as a matrix inside the phantom;

[0043]FIG. 23 is a perspective view illustrating the situation that theradiation of a radio wave from a radio transmitter is influenced, notonly by the phantom, but also by aerial condition during the scan;

[0044]FIG. 24 is a perspective view of an example of a phantom in theform of a flat plate which can be regarded as having an infinity size asfar as a radio transmitter is concerned;

[0045]FIG. 25 is a perspective view of an example of a scan mechanismwhich comprises a belt conveyor;

[0046]FIG. 26 is a perspective view of an example of a plurality ofelectromagnetic field probes disposed within the phantom and which aredisposed perpendicular to the direction of movement of the beltconveyor;

[0047]FIG. 27 is a perspective view of another example in which aplurality of electromagnetic field probes disposed within the phantomare disposed at an angle with respect to the direction of movement ofthe belt conveyor;

[0048]FIG. 28 is a perspective view of an example of an absorbed powermeasuring assembly comprising a plurality of phantoms which are formedto an equal configuration from an equal material and a plurality ofelectromagnetic field probes which are secured at different positionswithin the respective phantoms;

[0049]FIG. 29 is a perspective view of an example of an absorbed powermeasuring assembly comprising a plurality of phantoms formed to the sameconfiguration and from the same material and a plurality ofelectromagnetic field probes which are secured at an identical positionwithin the respective phantoms;

[0050]FIG. 30 is a perspective view of an example illustrating aposition detecting sensor which is mounted on the phantom;

[0051]FIG. 31 is a perspective view of an example in which a pluralityof position detecting sensors are mounted on the phantom in a manner tosurround the electromagnetic field probe;

[0052]FIG. 32 is a perspective view of a radio anechoic box in which anabsorbed power measuring assembly and a scan mechanism are entirelyconfined;

[0053]FIG. 33 is a perspective view of an example of a radio anechoicbox in which an absorbed power measuring assembly is confined andthrough which a belt conveyor passes; and

[0054]FIG. 34 is a perspective view of a modification of FIG. 33.

BEST MODES OF CARRYING OUT THE INVENTION First Invention

[0055] The principle of one aspect of the present invention will bedescribed first. When the head simulation phantom 2 which simulates theconfiguration and the electromagnetic characteristics of the head of thehuman body shown in FIG. 2 is irradiated with a radio wave in SHF band,which represents a transmission frequency of a mobile telephone, or witha radio wave of a higher frequency band, the absorption of the power bythe phantom 2 takes place in a manner indicated in FIG. 4. As shown, theabsorption will be greater in a surface layer 2 a of the head simulationphantom 2 which is located close to the radio transmitter 3, but will bereduced in the inner thin layer 2 b, and will be substantially equal tozero in the inside 2 c. Specifically, when a half-wavelength dipoleantenna is disposed at a distance of 10 mm with respect to the phantom 2having a diameter of 200 mm, for example, and a radio wave (of frequency900 MHz) is irradiated upon the phantom 2, it follows that denoting theabsorption of the power of the radio wave which occurs at the surface ofthe phantom 2 by 1, the absorption at a point which is removed 20 mmfrom the surface of the phantom will be reduced to {fraction (1/10)},and will be reduced to {fraction (1/100)} when removed 50 mm. In thismanner, most part of the phantom is not concerned with the measurementof absorbed power except for a very small portion which is located veryclose to the surface of the head simulation phantom 2. According to oneaspect of the present invention, an advantage is taken of this byreducing the volume and the weight of the head simulation phantom 2. Ifthere is a significant amount of absorption of the radio wave at alocation disposed deep inside the phantom 2, a reduction in the volumeof the phantom 2 will result in removing an internal portion where theabsorption of the radio wave is occurring to prevent the measurementfrom the inner portion. However, such likelihood is eliminated since theabsorption of the radio wave occurs only a portion thereof which islocated close to the surface. It is to be noted that eyes and nosedisplayed in phantom lines in FIG. 4 merely indicate that this phantomsimulates the head.

[0056] The fact that there is no problem when the volume of the phantom2 is reduced will be discussed below.

[0057] A model is considered as illustrated in FIG. 5. A sphere having adiameter of Dmm, a dielectric constant εr′=51.8 and a conductivityσ=1.43 S/m is used as a head simulation phantom 2. The phantom 2 isformed with a probe insertion opening 21 which extends from a point onthe surface through the center to a point close to the opposite surface.The probe insertion opening 21 has a diameter of 10 mm, and it isassumed that a distance from the inner end of the opening to the surfaceof the head simulation phantom 2 is equal to 10 mm. A half-wavelengthdipole antenna 5 is vertically disposed at a location which is spaced by10 mm from the surface of the head simulation phantom 2 which opposesthe inner end of the probe insertion opening 21. FIG. 6 graphicallyshows a result of calculation for a normalized power Pn (as referencedto the power which prevails for L=0), plotted against the height Lmmwhen the half-wavelength dipole antenna 5 is moved vertically up anddown from a reference point where the feed point is located opposite tothe inner end 21 a. The normalized power at the location where theelectromagnetic field probe 1 is disposed or at the inner end 21 a ofthe probe insertion opening 21 can be calculated according to thefinite-difference time-domain method (see, for example, “FiniteDifference Time Domain Method for Electromagnetics,” Karl S. Kung andRaymond J. Luebbers, CRC Press 1993 or the like). It is to be noted thatthe input power to the half-wavelength dipole antenna 5 is maintainedconstant, and the frequency of the radiated wave is 900 MHz. A curvewhich links o plots corresponds to a diameter D of the phantom 2 whichis equal to 200 mm (conventional one), a curve which links □ plotscorresponds to a diameter D equal to 100 mm, and a curve which links ⋄plots corresponds to D equal to 40 mm.

[0058] It will be seen that the normalized power distribution for D=100mm is substantially similar to the normalized power distribution of theconventional phantom in which D=200 mm.

[0059] Thus, it is considered that if the diameter of the headsimulation phantom 2 is reduced to one-half the conventional value, orif the volume and the weight are reduced to ⅛ times the conventionalvalue, it is still possible to simulate the head of a human body.

[0060] When the head simulation phantom 2 having D=100 mm ismanufactured, the volume will be 4×π×{(100/2)mm}³/3=5×10⁵ mm³, and itsweight will be 4×π×{(100/2)mm}³/3=5×10⁵ mm³ multiplied by 0.002 g/mm³ or1000 g when the solid dielectric 10′ is used, and the weight will befurther reduced to one-half when the liquid medium 10 is used. Theweight of the head simulation phantom 2 which is on the order of 500 gor 1000 g means that a measuring personnel can easily handle the phantom2 and move it for purpose of scan. When the diameter D is reduced toone-fifth or D=40 mm, the normalized power which is substantially equalto the conventional one having D=200 mm can be obtained if L is locatedwithin 20 mm. However, when the value of L increases to the order of 60mm, the normalized power will be nearly twice the normalized powerobtained with the conventional one having D=200 mm. The tendency thatthe normalized power increases above the value obtained with aconventional one having D=200 as the distance between the probe 1 andthe antenna feed point increases occurs for a diameter D which is equalto or less than 100 mm. However, if the required range of measurement Lis small, there is no problem. 25 When the range of measurement Lincreases, it is possible to reduce the weight and the cost requiredeven though the accuracy of measurement is degraded. It is to be notedthat with a phantom having a diameter D which is equal to or greaterthan 100 mm, there is a less contribution to reducing the weight and thecost required even though a higher accuracy can be obtained.

[0061] Consequently, in an embodiment of the present invention, aphantom 2 which simulates the configuration and the radio waveabsorption characteristics of part of the human body or the head in theexample to be described below comprises a phantom 2 as shown in FIG. 7Ain which a sphere is formed with the solid dielectric 10′ comprising thematerials mentioned above in connection with FIG. 2, for example. Inparticular, the volume of the phantom 2 is chosen to be equal to or lessthan ⅛ times the volume of part of the human body being simulated, orthe volume of the normal head of the human body or 5×10⁵ mm³. The lessthe volume of the phantom 2, the better in respect of reducing theweight, even though the accuracy of measurement becomes degraded asmentioned above. Accordingly, a minimum value for the volume of thephantom 2 may be chosen to be a volume which permits at least the probe1 to be contained even though the accuracy of measurement may bedegraded to a degree. A probe insertion opening 21 is formed extendingfrom a point on the surface of the phantom 2 and extending to anotherpoint located close to the surface, and an electromagnetic field probe 1is inserted into the probe insertion opening 21. For example, anadhesive 14 is filled into the probe insertion opening 21, thus securingthe electromagnetic field probe 1 within the phantom 2 to be integraltherewith.

[0062] It will be seen from the above description with reference to FIG.4 that a spacing D1 between the electromagnetic field probe 1 and theclosest surface of the phantom 2 be preferably within 20 mm, inparticular, within 10 mm in order to achieve a certain accuracy ofmeasurement. While it is preferred to have a smaller value for D1, asuitable value is chosen in consideration of the ease of manufacture anda resistance to fracturing. As indicated by single dot chain lines inthis Figure, a lead wire 1 a of the probe 1 is connected to acalculation and display unit 80 in the similar manner as a conventionalapparatus of this kind, and the calculation and display unit 80calculates and displays the absorbed power using the values detected bythe probe 1 and using the absorption effect.

[0063] As shown in FIG. 7B, a head simulation phantom 2 may beconstructed using a confined vessel 11 which simulates the configurationof the head and a liquid medium 10 which fills the vessel 11. The liquidmedium 10 may be similar to that mentioned previously in connection withFIG. 1. In this instance, the volume of the phantom 2 is again chosen tobe equal to or less than ⅛ times the volume of the normal head of thehuman body or 5×10⁵ mm³. The confined vessel 11 is formed with a probeinsertion opening 21 in the similar manner as in FIG. 7, into which anelectromagnetic field probe 1 is inserted and may be secured by using anadhesive 14, for example, to be integral with the phantom 2. The vessel11 is formed of a material such as acrylic resin or Teflon (registeredtrademark) having a low dielectric constant which is close to that ofthe air pereferably, thus preventing the distribution of a radio waveradiated from a radio transmitter 3 (not shown) from being disturbed. InFIGS. 7A and 7B, in order to connect the electromagnetic field probe 1to be integral with the phantom 2, other techniques than filling theadhesive 14 into the probe insertion opening 21 may be used to securethem together.

[0064] The spherical head simulation phantom 2 shown in FIGS. 7A and 7Bhas its volume reduced to or less than 5×10⁵ mm³ which corresponds to ⅛times the volume of the conventional phantom which represents the sizeof the head of the human body, and the weight is reduced to or less than⅛ times the weight of the conventional phantom, and thus is greatlyreduced in weight. The weight will be equal to or less than 500 g whenthe liquid medium 10 is used, and will be equal to or less than 1000 gwhen the solid dielectric 10′ is used. Accordingly, while the radiotransmitter 3 is retained by and fixed on a retainer 4 as illustrated inFIG. 8, a measuring personnel can hold the phantom 2 by one hand andeasily move it in the directions indicated by solid line arrows 8 inproximity to the radio transmitter 3 for purpose of scan. The locus ofscan 6 of the probe 1 is shown offset in this Figure. Alternatively, thephantom 2 may be fixed while the radio transmitter 3 may be moved indirections indicated by broken line arrows 8. The normalized powerdistribution will be substantially similar to the normalized powerdistribution of a conventional arrangement where D=200 mm. The volume ofthe solid dielectric 10′ or the volume of the confined vessel in whichthe liquid medium 10 is filled, which constitutes the head simulationphantom, is reduced, thus reducing the cost of materials and themanufacturing cost by a corresponding amount. In addition, because thephantom 2 is integral with the electromagnetic field probe 1, therelative positional relationship therebetween is easily reproducibleduring the scan movement.

[0065]FIG. 9 shows another embodiment of the invention. In thisembodiment, at least a portion of the surface of the head simulationphantom 2 shown in FIG. 7 which is located close to the radiotransmitter 3 or the surface portion located close to the location ofthe electromagnetic field probe 1 is coated by a thin spacer 22. Thespacer 22 may be adhesively secured or detachably mounted using a tackybonding agent or may be detachably mounted by fitting by choosing itsconfiguration. As shown in FIG. 10, the spacer 22 may coat substantiallythe entire surface of the head simulation phantom 2. The spacer 22 isconstructed with a material such as acrylic resin, Teflon (registeredtrademark), foamed styrol or wood which has a low dielectric constantclose to that of the air, thus minimizing a disturbance in thedistribution of the electromagnetic field which may occur by thepresence of the spacer 22.

[0066] With this construction, a relative movement can take place eithervertically or back-and forth, as viewed in FIG. 11, between the phantom2 and the radio transmitter 3 for purpose of scan while maintaining thehead simulation phantom 2 and the radio transmitter 3 in contact witheach other, thus maintaining a constant spacing therebetween andimproving the reproducibility of the measurement of absorbed power. Ifthe radio transmitter 3 is formed with a projection, which is appendedthereto, the head simulation phantom 2 can not be damaged by theprojection during the scan which takes place in contact therewith, thuspreventing any damage of a sensor of the electromagnetic field probe 1from occurring. When the spacer 22 is formed around the entire surfaceof the phantom 2, as shown in FIG. 10, the spacer 22 is effective toprotect the phantom 2 from mechanical damage.

[0067] The thickness of the spacer 22 simulates the thickness of the earof the human body or simulates the thickness of a cover applied to theradio transmitter 3, serving the both simulations. Accordingly, it isdesirable that the spacer 22 has a thickness which is on the order of 20mm at maximum and on the order of 1 mm at minimum, and by changing thethickness of the spacer 22, a variety of simulations can take place. Byway of example, as shown in FIG. 12, a plurality of semi-sphericalspacers 22 having mutually different thicknesses may be provided, andare mounted on the phantom 2 in a detachable manner. FIGS. 12A, 12B and12C illustrate that sequentially thicker spacers 22 are mounted in aninterchangeable manner.

[0068] By way of example, as shown in FIG. 13, three spacers 22 a, 22 band 22 c are stacked one above another and are coupled together in aslidable manner. Such coupling is achieved by removing both lateraledges of the spacer 22 a which are located toward the spacer 22 b alongthe length thereof to define a wedge-shaped coupler 24 while the surfaceof the spacer 22 b which is disposed toward the spacer 22 a is formedwith a coupling recess 25 in which the wedge-shaped coupler 24 isreceived in the manner of a wedge, thus allowing the spacers 22 a and 22b to slide relative to each other along their length while securing themtogether in the direction of the thickness. A similar wedge-shapedcoupling takes place between the spacers 22 b and 22 c to couple them ina slidable manner in the direction of the length while securing themtogether in the direction of the thickness.

[0069] As shown in FIG. 14, these spacers 22 a, 22 b and 22 c which arestacked one above another are mounted on the phantom 2 so as to beinterposed between the phantom 2 and the radio transmitter 3. With thisarrangement, by sliding the spacers, it is possible to interpose onlythe spacer 22 a between the phantom 2 and the radio transmitter 3, tointerpose both spacers 22 a and 22 b as shown in FIG. 14 or to interposethe spacers 22 a, 22 b and 22 c. In this manner, the thickness of thespacer 22 which is interposed between the phantom 2 and the radiotransmitter 3 can be changed. The number of stacked spacer 22 is notlimited to three, but may be suitably increased or decreased, and theindividual thickness of the stacked spacers 22 a, 22 b and 22 c can bechosen to be different from each other.

[0070] As shown in FIG. 15A, a handle 23 is secured, for example,adhesively, to the open end of a probe insertion opening 21 in thephantom 2 and extends in the direction opposite from the probe insertionopening 21 to make the radio wave which is radiated from the radiotransmitter 3 to be free from the influence of the hand 4′ as the hand4′ is moved away from the radio transmitter 3 when the hand 4′ of ameasuring personnel is brought close to the handle 23 for purpose ofscan and measurement as illustrated in FIG. 8, for example. The handle23 is formed of a material having a low dielectric constant such asacrylic resin, fluorine containing resin, foamed styrol resin or wood.The lead wire 1 a of the electromagnetic field probe 1 is passed throughan opening 26 which is formed inside the handle 23 in communication withthe probe insertion opening 21. In this instance, an adhesive 14 isfilled into the opening 26 to secure the probe 1 to the phantom 2. Asshown in FIG. 15B, the handle 23 may be mounted on the phantom 2 so asto extend in a direction perpendicular to the direction in which theprobe insertion opening 21 extends.

[0071] The configuration of the head simulation phantom 2 is not limitedto the sphere mentioned above, but may assume a geometrically simpleconfiguration such as an ellipsoid as shown in FIG. 16A, a cube as shownin FIG. 16B, a rectangular body as shown in FIG. 16C or a solid cylinderas shown in FIG. 16D as long as the purpose of simulating the head ofthe human body is served. In any event, it has a volume which is on theorder of ⅛ times the volume of the head of a normal man or less, namely,5×10⁵ mm³. Rather than being limited to a phantom which simulates thehead of the human body, a simulation phantom having a configuration asillustrated in FIGS. 16A to D may be constructed to simulate part of thehuman body such as the arm or trunk. In any event, it has a volume whichis equal to or less than ⅛ times the normal volume of part of the humanbody being simulated.

[0072] By constructing the phantom as a sphere or a geometrically simpleconfiguration as illustrated in FIGS. 16A to D, a distribution of theelectromagnetic field within the phantom 2 which is not formed with aprobe insertion opening 21 may be analytically obtained using the radiotransmitter 3 as a dipole antenna, and a calibration factor for theelectromagnetic field probe 1 can be determined on the basis of suchanalytical results.

[0073] By constructing a phantom 2 which simulates the configuration ofthe head of the human body, or simulating the front face of the head bya square-shaped plane 2 a as a front surface as shown in FIG. 17A,forming a probe insertion opening 21 so that it extends from the rearside to a point close to the front surface 2A and inserting anelectromagnetic field probe 1 therein, an absorbed power measuringassembly 7 which can be used with a transceiver as the radio transmitter3 may be constructed. Eyes and nose indicated by single dot chain linesmay assume configurations which correspond to actual eyes and nose, ormay be a simple plane with dot indications thereon which represents thefront face for the sake of convenience. Alternatively, as shown in FIG.17B, the square-shaped plane 2 a may be provided as a front surfacewhich simulates the lateral side of the face of the head and anelectromagnetic field probe 1 may be inserted therein to construct anabsorbed power measuring assembly 7 which can be used when utilizing amobile telephone as the radio transmitter 3. The ear indicated by singledot chain lines may be configured so as to correspond to the actual ear,or may be a simple plane with a dot indication representing the lateralside of the face for the sake of convenience. When the configuration isrelatively complex as in such a phantom, a distribution of theelectromagnetic field cannot be analytically obtained to determine acalibration factor for the electromagnetic field probe 1, but thefinite-difference time-domain method may be used to derive adistribution of the electromagnetic field numerically, and a calibrationfactor for the electromagnetic field probe 1 can be determinedtherefrom.

[0074] While the above description has principally dealt withconstructing the phantom 2 with the solid dielectric 10′, the phantom 2of a type in which the liquid medium 10 is confined into the enclosedvessel 11 as shown in FIG. 7B may be used as phantoms which are used inthe embodiments shown in FIGS. 9 to 17. In this instance, since theliquid medium 10 is sealed, an aging effect in the electromagneticcharacteristics which may result from the evaporation of components canbe prevented while facilitating the handling.

Second Invention

[0075]FIG. 18 shows an embodiment of another aspect of the invention,and parts corresponding to those shown in FIGS. 1 to 17 are designatedby like reference characters as used before.

[0076] A phantom 2 which simulates the electromagnetic characteristicsof the human body is provided. In this instance, there is no need tosimulate the configuration of part of the human body. FIG. 18 representsan arrangement in which the phantom 2 is formed with the soliddielectric 10′ in the form of a relatively flat cube. A probe insertionopening 21 is formed into one surface of the phantom 2 and extends closeto the opposite surface 2 a. An electromagnetic field probe 1 isinserted into and secured in the inner end of the probe insertionopening 21, thus constructing an absorbed power measuring assembly 7.Securing the electromagnetic field probe 1 may take place, for example,by way of the adhesive 14 as illustrated in FIG. 7A.

[0077] A radio transmitter 3 is disposed in proximity to the location ofthe electromagnetic field probe 1 within the phantom 2, and a scan takesplace by a scan mechanism 100 while the radio transmitter 3 is disposedopposite to the phantom 2. In the example shown in FIG. 18, the radiotransmitter 3 is disposed close to and in parallel relationship with thesurface 2 a of the phantom 2 which is located close to the probe 1 whilean antenna 5 of the radio transmitter 3 such as a mobile telephoneextracts from a casing 3 a. The radio transmitter 3 is mounted so thatthe casing 3 a is held gripped by a retainer 4.

[0078] The scan mechanism 100 may comprise drive screws 121, 122extending along a pair of parallel sides of a rectangular frame-shapedbase 110, for example, and rotatably mounted by four supports 111.Similarly, drive screws 123, 124 are rotatably mounted by the supports111 on the other pair of parallel sides. A support bar 131 which extendsparallel to the drive screws 121, 122 is formed with threaded holes atits opposite ends, which are threadably engaged with the drive screws121, 122. Also, a support bar 132 which extends parallel to the drivescrews 123, 124 is formed with threaded holes at its opposite ends,which are threadably engaged with the drive screws 123, 124. The supportbars 131 and 132 are slightly offset from each other in a directionperpendicular to the surface of the phantom 2 which is disposed oppositeto the radio transmitter.

[0079] As shown in FIG. 18B, pairs of opposing, inverted L-shapedengaging peaces 141 a and 141 b, 141 c and 141 d, 142 a and 142 b, and142 c and 142 d are fixedly mounted on the surface 2 a of the retainer 4which is disposed opposite from the phantom 2, and the support bar 131passes between the pairs of engaging pieces 141 a and 141 b and 141 cand 141 d so as to be slidable between the ends of these engaging piecesand the surface 2 a of the retainer 4. In the similar manner, thesupport bar 132 is passed between the pairs of engaging pieces 142 a and142 b and 142 c and 142 d so as to be slidable. However, it is to benoted that the support bar 132 has its opposite lateral edges receivedin grooves formed in the ends of the engaging pieces 142 a-142 d,whereby its movement in a direction perpendicular to the surface 2 a ofthe retainer is restricted.

[0080] An arrangement is made such that the drive screws 121, 122 can bedriven for rotation in forward and reverse directions by a controller151 including a motor for example, and the drive screws 123, 124 can bedriven for rotation in forward and reverse directions by a similarcontroller 152. An absorbed power measuring assembly 7 is mounted on asupport 160 which is secured to the base 110 so that the surface 2 a ofthe phantom 2 is disposed close to and opposite to the radio transmitter3 which is retained by the retainer 4.

[0081] Accordingly, when the drive screws 121, 122 rotate, the supportbar 131 moves along the screws 121, 122 depending on the direction ofrotation thereof, whereby the radio transmitter 3 also moves in the samedirection. When the drive screws 123, 124 rotate, the support bar 132moves along the screws 123, 124 depending on the direction of rotationthereof, whereby the radio transmitter 3 also moves in the samedirection. Thus, by controlling the controllers 151, 152, atwo-dimensional scan of the probe 1 relative to the radio transmitter 3can take place, as indicated by a locus 6 which is shown offset in thisFigure. For example, the two-dimensional scan is capable of measuringthe power absorbed from the radio wave over the entire surface 2 a ofthe phantom 2 while the antenna feed point 3 b of the radio transmitter3 is disposed opposite to the probe 1. FIG. 19 illustrates by way ofexample that an area 9, shown hatched, over the surface 2 a of thephantom 2 can be measured relative to the radio transmitter 3. It is tobe noted that what is measured by the electromagnetic field probe 1 isvalues on the locus of scan 6, and values in interstices S betweenadjacent scan lines are interpolated from adjacent measured values. Inorder to reduce the time of measurement, rather than using a continuousmeasurement, the measurement takes place at an interval on the scanline, and values in the interval are interpolated from adjacent measuredvalues. The spacing between the adjacent scan lines may be chosen on theorder of 1 cm, for example. The range of measurement (area) 9 ispreferably a rectangular range which is determined by the longitudinallength (inclusive of the antenna length) and the lateral length of theradio transmitter 3.

[0082] The phantom 2 used may comprise an enclosed vessel 11 which isconfigured in the similar manner as shown in FIG. 18A and which isformed with a probe insertion opening 21, into which a liquid medium 10is filled, as shown in FIG. 20.

[0083] The scan mechanism 100 allows a two-dimensional scan of theabsorbed power measuring assembly 7 relative to the radio transmitter,and accordingly, the power absorbed from the radio wave by each part ofthe human body which corresponds to the phantom 2, can be measured witha high positional accuracy. In addition, a result which is similar to aresult of measurement according to the measuring technique shown in FIG.1 in which the probe 1 is moved for purpose of scan is obtained and thelikelihood that the response of the liquid medium 10 may be changed dueto the evaporation is avoided with the phantom 2 which uses the liquidmedium 10. The scan mechanism 100 is not limited to the exampledescribed above, but a variety of X·Y drive mechanism may be used.

[0084] As shown in FIG. 21, a plurality of electromagnetic field probes1 are fixedly mounted in a linear array within a phantom 2. A movingscan of a radio transmitter 3 obtains a range of measurement shown inFIG. 19 with a stroke corresponding to a spacing S1 between theelectromagnetic field probes 1 in the direction of the array of theelectromagnetic field probes 1. In FIG. 21, the probes 1 are arrayed ina direction parallel to the lengthwise direction of the radiotransmitter 3, but may be arrayed in a direction perpendicular to thelengthwise direction.

[0085] As shown in FIG. 22, a plurality of electromagnetic field probes1 may be arrayed in a matrix in a plane which is close to the surface 2a of a phantom 2. In this instance, a measurement over the range shownin FIG. 19 can be obtained by scanning in one direction of the array ofthe electromagnetic probes 1 through a stroke corresponding to a spacingS1 and scanning in the other direction of the array through a strokecorresponding to a spacing S2. Again, a value or values located betweenmeasuring points are interpolated from adjacent measured values. Inconsideration of these, the number of probes 1 which are disposed withinthe phantom 2 is contemplated to be from 1 to the order of 10, and thespacing between the probes are preferably S1=S2=20 mm or so.

[0086] With the arrangement shown in FIG. 21, the scan stroke is shorterthan in the example shown in FIG. 18, and the measurement can becompleted in a shorter time interval and a scan mechanism 100 can beconstructed in a compact form. With the embodiment shown in FIG. 22, thetime interval of measurement can be made shorter and the scan mechanismcan be constructed in a smaller size.

[0087] As indicated in FIG. 23, when a radio transmitter 3 is brought toa position A during a moving scan or when the majority of the radiotransmitter 3 is located opposite to a phantom 2, the radiationcharacteristics of the radio transmitter 3 is strongly influenced by thephantom 2, but at position B or when a significant portion of the radiotransmitter 3 is not disposed opposite to the phantom 2 or misalignedtherewith, the radiation characteristics of the radio transmitter 3 isinfluenced by both the phantom 2 and the air.

[0088] In consideration of this, as illustrated in FIG. 24, theconfiguration of a phantom 2 may be chosen to be in the form of a flatplate having an infinity size as seen by a radio transmitter 3, with theradio transmitter 3 disposed opposite to a central portion of onesurface of the plate-shaped phantom 2. In this manner, the influence ofthe phantom upon the radiation characteristics of the radio transmitter3 can be made substantially uniform at any position of the radiotransmitter 3 during its moving scan. When part of the human body whichis located close to the radio transmitter 3 is more planar and its areais greater, the absorption of the radio wave occurs more strongly.Accordingly, when an absorbed power measuring apparatus is constructedin the manner shown in FIG. 24, a maximum value evaluation can be made.In order for the phantom 2 to be viewed by the radio transmitter 3 ashaving an infinity size, its length L1 as measured in the direction inwhich an antenna 5 extends should be equal to or greater than 0.6λ, itslength L2 in a direction perpendicular to the antenna 5 should be equalto or greater than 0.5λ, and its thickness L3 should be equal to orgreater than 0.3λ where λ represents the wavelength of a radio wavetransmitted from the radio transmitter 3.

[0089] The phantom 2 may be one which simulates respective part of anactual human body as illustrated in FIGS. 7, 16 and 17 or one whichemploys an geometrically simple configuration. However, it is notnecessary that the volume of the phantom 2 be equal to the volume of acorresponding part of the human body. In any event, the measurementtakes place by a moving scan of the absorbed power measuring assembly 7and the actual line transmitter 3 relative to each other using the scanmechanism 100 shown in FIG. 18 or the like, for example.

[0090] The use of a belt conveyor in a scan mechanism 100 is illustratedin FIG. 25. A belt conveyor 31 is maintained substantially horizontalacross its width and runs substantially horizontally. A drive mechanismfor the belt conveyor 31 is not shown in the drawing. A phantom 2 asmounted on a support 160 is fixedly mounted over the belt conveyor 31.The surface 2 a of the phantom 2 which is located close to a probe 1 isdisposed opposite to the belt conveyor 31 with a spacing D1 with respectto the top surface of the belt conveyor 31. The radio transmitter 3 isplaced on the belt conveyor 31 so that its lengthwise direction extendsin the crosswise direction of the belt conveyor 31 and the direction ofthickness of a casing 3 a extends perpendicular to the top surface ofthe belt conveyor 31. Substantially the entire length of the radiotransmitter 3 passes under the phantom 2, and the spacing D1 is chosenso that the surface 2 a of the phantom 2 is disposed as close to theradio transmitter 3 as possible.

[0091] The radio transmitter 3 is placed on an upstream portion of thebelt conveyor 31, and as the radio transmitter 3 passes under thephantom 2, a linear scan takes place between the radio transmitter 3 andan absorbed power measuring assembly 7, thus enabling a measurement.With this arrangement, when radio transmitters 3 are successively placedon the belt conveyor 31, a measurement of the power absorbed by thephantom 2 can be automatically made for a number of radio transmitters3.

[0092] As shown in FIG. 26, when a plurality of electromagnetic fieldprobes 1 are disposed within a phantom 2 as an array in a crosswisedirection of the belt conveyor 31, merely placing a radio transmitter 3on the belt conveyor 31 allows a range of measurement of absorbed powercan be extended to a two-dimensional plane. In addition, as shown inFIG. 27, when a plurality of electromagnetic field probes 1 are disposedas an oblique array with respect to the crosswise direction of the beltconveyor 31, the electromagnetic field probes 1 can be kept far awayfrom each other. This allows a reduction in the equivalent dielectricconstant and the conductivity of the phantom 2 under the influence ofthe probe insertion opening 21 which is used to secure theelectromagnetic field probe 1 to be alleviated. In this instance, aphantom 2 in the form of a flat plate has an infinity size as viewedfrom the radio transmitter 3, thus preventing the radiationcharacteristics of the radio transmitter 3 and the antenna reflectedpower from changing as long as the radio transmitter 3 is disposedopposite to the phantom 2.

[0093] As shown in FIG. 28, a plurality of phantoms 2, which may bethree in number, having an identical configuration and formed of anidentical material are fixedly mounted as an array in a direction inwhich a belt conveyor 31 runs. However, an electromagnetic field probe 1is fixedly mounted in each phantom 2 at a mutually different position asviewed in the crosswise direction of the belt conveyor 31. In thisinstance, the phantom 2 has a size which corresponds to a part of thehuman body. For example, the phantom 2 shown in FIGS. 2, 18A and 20 maybe used. In this manner, measured values from the two-dimensional scaninclude contributions of configuration of the part of the human bodywhile the response of each phantom 2 is little influenced by theelectromagnetic field probes 1. The shift of position of theelectromagnetic field probes 1 between different phantoms 2 may bechosen in the running direction rather than in the crosswise directionof the belt conveyor, or may be chosen in any other suitable manner.

[0094] As shown in FIG. 29, a plurality of phantoms 2, which may bethree in number, for example, having an identical configuration andformed with an identical material may be fixedly mounted as an array inthe running direction of the belt conveyor 31, and an electromagneticfield probe 1 is mounted at the same position, for example, at thecenter of each phantom 2. As the belt conveyor 31 runs, each radiotransmitter 3 is subject to the measurement of absorbed power by threeabsorbed power measuring assemblies 7 under the same condition. A meanvalue of a plurality of measured values for each radio transmitter 3 maybe chosen to define the power absorbed from the radio wave from thisradio transmitter 3, or a maximum value among a plurality of measuredvalues for each radio transmitter 3 may be chosen to define the powerabsorbed from the radio wave from this radio transmitter 3. The processof determining such a mean value or a maximum value takes place in thecalculation and display unit 80 shown in FIG. 7.

[0095] In an example shown in FIG. 30, a position sensor 51 is mountedon a phantom 2 in order to improve the accuracy of measuring position.The position sensor 51 is mounted on the phantom 2 so that its positionrelative to the probe 1 can be defined, thus detecting whether or notthe position sensor 5 1 is located opposite to a radio transmitter 3.The position sensor 51 detects whether or not it is located opposite tothe radio transmitter 3 by radiating an infrared pulse beam in adirection perpendicular to the surface 2 a of the phantom 2, forexample, and determining a time interval until a reflected infraredpulse is received or the strength of the reflected infrared pulse. As ascan mechanism performs a two-dimensional moving scan of the radiotransmitter 3, each point where the radio transmitter 3 has beendetected can be plotted, whereby the configuration of the radiotransmitter 3 which opposes the phantom 2 is detected. Since therelative position between the probe 1 and the position sensor 51 in aplane parallel to the scan plane is fixed and is previously known, theposition of each measuring point of the probe 1 with respect to theconfiguration of the detected radio transmitter 3 can be determined, andwhen the configuration of the radio transmitter 3 is determined with ahigh accuracy, the position of the measuring point of the probe 1 can bedetermined with a corresponding accuracy.

[0096] When the belt conveyor 31 shown in FIG. 25 is used as the scanmechanism, running the belt conveyor 31 at a constant speed and placingradio transmitters 3 on the belt conveyor 31 at a given time intervalallows the time to be determined when a particular radio transmitter 3reaches the position of the probe 1, by dividing the distance betweenthe position where the radio transmitter 3 is placed on the beltconveyor 31 and the absorbed power measuring assembly 7 by the runningspeed of the belt conveyor 31. In this instance, if the position sensor51 is also used in the absorbed power measuring assembly 7 as shown inFIG. 30, the measuring position of the probe 1 relative to the radiotransmitter 3 can be correctly determined by detecting the arrival ofthe radio transmitter 3 by the position sensor 51, if the position wherethe radio transmitter 3 is placed on the belt conveyor 31 is misalignedor the time interval to place it is offset.

[0097] As shown in FIG. 31, by disposing the position sensors 51 so asto surround the probe 1, the positional relationship between the radiotransmitter 3 and the probe 1 can be determined with a better accuracy.

[0098]FIG. 32 shows an exemplary construction in which an absorbed powermeasuring assembly 7 and a scan mechanism 100 are enclosed in a radioanechoic box 41. With this construction, it is possible to prevent anelectromagnetic field probe 1 from detecting undesired radio waves andto prevent a leakage of the radio wave radiated by a radio transmitter 3to the exterior.

[0099] When the scan mechanism is constructed with the belt conveyor 31,a pair of opposing walls of the radio anechoic box 41 are formed withopenings 41 a, 41 b in opposing relationship so as to pass the beltconveyor 31 therethrough, and metal tubes 42 a, 42 b are mounted toconnect with the openings 41 a, 41 b, as shown in FIG. 33. The openingsof the tubes 42 a, 42 b are chosen so that their cut-off frequency ishigher than the frequency of the radio wave radiated from the radiotransmitter 3 within the radio anechoic box 41, thus preventing theradio wave from the radio transmitter 3 from passing through the tubes42 a, 42 b. Alternatively, cloths 43 a, 43 b woven with metal areattached to the upper edges of the openings 41 a, 41 b of the radioanechoic box 41 to hang therefrom, as shown in FIG. 34, thus causing thecloths 43 a, 43 b to be forced out of the way by the radio transmitter 3as it passes through the openings 41 a, 41 b.

[0100] A phantom using the liquid medium 10 as well as the soliddielectric 10′ may be used also in the embodiments shown in FIGS. 21 to34. It is also desirable according to the second invention that theprobe 1 be disposed within 20 mm from the surface 2 a of the phantomwhich faces the radio transmitter 3.

What is claimed is:
 1. An apparatus for measuring absorbed powerincluding an electromagnetic field probe inserted within a phantom whichsimulates the configuration and the electromagnetic characteristics ofpart of a human body, and wherein the strength of an electric field or amagnetic field of a radio wave which is externally irradiated upon thephantom is measured by the electromagnetic field probe and the power ofa radio wave absorbed by the part of the human body is estimated on thebasis of measured values; wherein the phantom and the electromagneticfield probe are integrally connected together.
 2. An apparatus formeasuring absorbed power according to claim 1 in which the phantom has avolume which is equal to or less than ⅛ times the volume of the part ofthe human body.
 3. An apparatus for measuring absorbed power accordingto claim 1 in which at least a portion of the phantom which is locatedtoward a radiation source of the irradiating radio wave is attached witha spacer comprising a material of a low dielectric constant.
 4. Anapparatus for measuring absorbed power according to claim 3 in which thespacer has a thickness in a range from 1 to 20 mm.
 5. An apparatus formeasuring absorbed power according to claim 3 in which the spacer isdetachable.
 6. An apparatus for measuring absorbed power according toclaim 3 in which the spacer has a variable thickness.
 7. An apparatusfor measuring absorbed power according to one of claims 1 to 6 in whichthe part of the human body represent a head and the phantom has a volumewhich is equal to or less than 5×10⁵ mm³.
 8. An apparatus for measuringabsorbed power according to one of claims 1 to 6 in which theelectromagnetic field probe is disposed within 20 mm from the surface ofthe phantom which is disposed toward a radiation source of theirradiating radio wave.
 9. An apparatus for measuring absorbed poweraccording to one of claims 1 to 6 in which the phantom is attached witha handle which is formed of a material having a low dielectric constant.10. An apparatus for measuring absorbed power including anelectromagnetic field probe disposed within a phantom which simulatesthe electromagnetic characteristics of a human body, and wherein thestrength of an electric field or a magnetic field of a radio waveexternally irradiated upon the phantom is measured by theelectromagnetic field probe, and the power of the radio wave absorbed bythe human body is estimated on the basis of measured values; furthercomprising a scan mechanism which causes a relative movement between thephantom and a radio transmitter.
 11. An apparatus for measuring absorbedpower according to claim 10 in which a plurality of electromagneticfield probes are disposed within the phantom.
 12. An apparatus formeasuring absorbed power according to claim 10 or 11 in which thephantom is in the form of a flat plate and has a size of substantiallyinfinity relative to the size of the radio transmitter acting as aradiation source of the irradiating radio wave.
 13. An apparatus formeasuring absorbed power according to claim 10 in which the scanmechanism comprises a belt conveyor, and the phantom is fixedly mountedin opposing relationship with the belt conveyor while the radiotransmitter acting as a radiation source of the irradiating radio waveis placed on a surface of the belt conveyor which faces the phantom. 14.An apparatus for measuring absorbed power according to claim 13 in whicha plurality of electromagnetic field probes are disposed as an array inthe crosswise direction of the belt conveyor.
 15. An apparatus formeasuring absorbed power according to claim 13 in which the phantom isin the form of a flat plate having a size of substantially infinityrelative to the size of the radio transmitter, and a plurality ofelectromagnetic field probes are disposed as an oblique array relativeto the crosswise direction of the belt conveyor.
 16. An apparatus formeasuring absorbed power according to claim 13 in which a plurality ofidentical phantoms are fixedly mounted as an array in the runningdirection of the belt conveyor, and the electromagnetic field probesdisposed within the respective phantoms assume a different position ineach phantom.
 17. An apparatus for measuring absorbed power according toclaim 13 in which a plurality of identical phantoms are fixedly mountedas an array in the running direction of the belt conveyor, and theelectromagnetic field probes disposed within the respective phantomsassume an identical position.
 18. An apparatus for measuring absorbedpower according to one of claims 10, 11, 13, 14, 16 and 17 in which thephantom has a configuration which simulates the configuration of thepart of the human body.
 19. An apparatus for measuring absorbed poweraccording to one of claims 10, 11 and 13 to 17; further comprising aposition sensor disposed in the phantom for detecting the presence orabsence of a radio transmitter acting as a radiation source of theirradiating radio wave.
 20. An apparatus for measuring absorbed poweraccording to one of claims 10, 11 and 13 to 17; further comprising aradio anechoic box in which the phantom and the scan mechanism arecontained.